Make IOSink implement StringSink

tests/standalone/io/process_broken_pipe_test.dart

Index: tests/standalone/io/process_broken_pipe_test.dart
diff --git a/tests/standalone/io/process_broken_pipe_test.dart b/tests/standalone/io/process_broken_pipe_test.dart
index 3833158379f4f9f0e4c48f8dd29dc93c07e43d14..4db19ac917a9dd0e0fa6791c6cd231b75022349e 100644
--- a/tests/standalone/io/process_broken_pipe_test.dart
+++ b/tests/standalone/io/process_broken_pipe_test.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
@@ -24,7 +24,7 @@ main() {
     // Write to the stdin after the process is terminated to test
     // writing to a broken pipe.
     process.exitCode.then((code) {
-      process.stdin.add([0]);
+      process.stdin.writeBytes([0]);
     });
   });
 }